This is a 1996 F-150 300cuin 6 4x4 recently purchased in poor to fair condition.
The problem is even with a new headlight switch installed, the odometer and interior light do not work....worse yet, both of these will come on if you pull the headlight know out all the way then press it back in maybe 1/4". There is no function of these unless the above procedure is followed. We have tried 3 new headlight switches-same result.

Where can I get a full schematic so I can trace out the harness. It obviously is not an issue with the switch. The PO was somewhat of a ham fisted blacksmith and may have tangled with some of the wiring by the firewall. Any help would be appreciated.
Thanks